1. Field of the Invention
The present invention relates a process cartridge and an electrophotographic image forming apparatus.
An electrophotographic image forming apparatus forms an image on a recording medium by using the electrophotographic image forming process. Examples of an electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (e.g., a laser beam printer and an LED printer), a facsimile apparatus, and a word processor.
A process cartridge may be a cartridge into which charging means, developing means, or cleaning means and an electrophotographic photosensitive member are integrally incorporated, and which is detachably mountable to the main body of an electrophotographic image forming apparatus. Alternatively, the process cartridge may be a cartridge into which at least one of the charging means, the developing means, and the cleaning means and the electrophotographic photosensitive member are incorporated, and which is detachably mountable to the main body of the electrophotographic image forming apparatus. Further alternatively, the process cartridge may be a cartridge into which at least the developing means and the electrophotographic photosensitive member are incorporated, and which is detachably mountable to the main body of the electrophotographic image forming apparatus.
2. Description of Related Art
When an electrophotographic image forming apparatus has been used for a long period of time, it is necessary to perform replacement of the photosensitive drum, replenishment or replacement of the developer, and adjustment, cleaning, and replacement of other components (such as the charger and cleaner container).
In view of this, an image forming apparatus using the electrophotographic image forming process adopts a process cartridge system in which an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member are integrated into a cartridge, which is detachably mountable to the main body of the image forming apparatus. In the process cartridge system, the user can perform maintenance on the apparatus in person without depending on a serviceman, whereby a substantial improvement can be achieved in terms of operability. Thus, the process cartridge system is widely used for image forming apparatuses.
As shown in FIG. 15, in a conventional process cartridge 45, a development frame 43 supporting developing means, such as a developing roller 18, and a toner container 46 are joined together by ultrasonic welding to form a development unit. Then, a cleaning unit formed by mounting a photosensitive drum 11 and a charging roller 12 to a cleaning frame 47 is joined to the development unit by a pivot 49. Then, a compression spring (not shown) is provided between the cleaning frame 47 and the development frame 43, biasing the photosensitive drum 11 and the developing roller 18 toward each other.
Such a process cartridge is detachably mountable to the main body of an image forming apparatus. In a cartridge detachably mountable system in which the cartridge is mounted to and detached from the front surface of the main body of an image forming apparatus, the danger of the laser beam leaking to the exterior may be conceived if the cartridge is simply inserted. In view of this, there has been proposed a double laser beam shielding mechanism (Japanese Patent Application Laid-open No. 6-106772 and Japanese Patent Application Laid-open No. 6-202393. However, use of a conventional laser beam shielding mechanism operationally connected with the attachment and detachment of the cartridge may result in a rather complicated mechanism.
It is an object of the present invention to provide an electrophotographic image forming apparatus in which a laser beam does not leak to the exterior of the apparatus main body and a process cartridge detachably mountable to the apparatus main body.
Another object of the present invention is to provide an electrophotographic image forming apparatus in which a process cartridge is mounted to the apparatus main body and in which, when an opening/closing member that can be opened and closed with respect to the apparatus main body is closed, an optical path for a laser beam is opened to allow passage of the laser beam, and a process cartridge detachably mountable to the apparatus main body.
Still another object of the present invention is to provide a process cartridge which has an abutting portion which, when the process cartridge is mounted to the main body of an image forming apparatus by dropping the process cartridge in the main body, abuts a means for moving a shielding member shielding an optical path for a laser beam from a shielding position to a retracted position, and an electrophotographic image forming apparatus to which the process cartridge is detachably mountable.
These and other objects, features and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.